package com.lenl.datastruct.tree;


/**
 * @author Lenl
 * @version v1.0
 * @create 2022-05-03 21:29
 * @description 二叉树前序中序后序遍历
 */
public class BinaryTreeDemo {
    public static void main(String[] args) {
        //创建二叉树
        BinaryTree binaryTree=new BinaryTree();
        //创建节点
        HeroNode root=new HeroNode(1,"宋江");
        HeroNode node2=new HeroNode(2,"吴用");
        HeroNode node3=new HeroNode(3,"卢俊义");
        HeroNode node4=new HeroNode(4,"林冲");
        HeroNode node5=new HeroNode(5,"关胜");
        //先手动创建二叉树，后面会用递归方式创建二叉树
        root.setLeft(node2);
        root.setRight(node3);
        node3.setRight(node4);
        node3.setLeft(node5);
        binaryTree.setRoot(root);
        //测试
        System.out.println("前序遍历：");
        binaryTree.preOrder();
        System.out.println("中序遍历：");
        binaryTree.infixOrder();
        System.out.println("后序遍历：");
        binaryTree.postOrder();

        System.out.println("前序遍历查找：");
        HeroNode preResult= binaryTree.preOrderSearch(5);
        if(preResult!=null){
            System.out.println("找到了，信息为："+preResult);
        }
        System.out.println("中序遍历查找：");
        HeroNode infixResult=binaryTree.infixOrderSearch(5);
        if(infixResult!=null){
            System.out.println("找到了，信息为："+infixResult);
        }
        System.out.println("后序遍历查找");
        HeroNode postResult=binaryTree.postOrderSearch(5);
        if(postResult!=null){
            System.out.println("找到了，信息为："+postResult);
        }

        System.out.println("测试删除");
        binaryTree.delNode(5);
        binaryTree.preOrder();

    }
}

//定义一个BinaryTree
class BinaryTree{
    private HeroNode root;

    public HeroNode getRoot() {
        return root;
    }

    public void setRoot(HeroNode root) {
        this.root = root;
    }
    //前序遍历
    public void preOrder(){
        if(this.root!=null){
            this.root.preOrder();
        }else{
            System.out.println("二叉树为空，无法遍历");
        }
    }
    //中序遍历
    public void infixOrder(){
        if(this.root!=null){
            this.root.infixOrder();
        }else{
            System.out.println("二叉树为空，无法遍历");
        }
    }
    //后序遍历
    public void postOrder(){
        if(this.root!=null){
            this.root.postOrder();
        }else{
            System.out.println("二叉树为空，无法遍历");
        }
    }

    //谦虚查找
    public HeroNode preOrderSearch(int no){
        if(this.root!=null){
            return  this.root.preOrderSearch(no);
        }else{
            return null;
        }
    }
    //中序遍历
    public HeroNode infixOrderSearch(int no){
        if(this.root!=null){
            return this.root.infixOrderSearch(no);
        }else{
            return null;
        }
    }
    //后序遍历
    public HeroNode postOrderSearch(int no){
        if(this.root!=null){
            return this.root.postOrderSearch(no);
        }else{
            return null;
        }
    }

    //删除节点
    public void delNode(int no){
        if(root==null){
            System.out.println("空树，不能删除！");
        }else{
            if(root.getNo()==no){
                root=null;
            }else{
                root.delNode(no);
            }
        }
    }


}

//创建HeroNode节点
class HeroNode{
    private int no;
    private String name;
    private HeroNode left;
    private HeroNode right;

    public HeroNode(int no, String name) {
        this.no = no;
        this.name = name;
    }

    public int getNo() {
        return no;
    }

    public void setNo(int no) {
        this.no = no;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public HeroNode getLeft() {
        return left;
    }

    public void setLeft(HeroNode left) {
        this.left = left;
    }

    public HeroNode getRight() {
        return right;
    }

    public void setRight(HeroNode right) {
        this.right = right;
    }

    @Override
    public String toString() {
        return "HeroNode{" +
                "no=" + no +
                ", name='" + name + '\'' +
                '}';
    }

    //递归删除节点
    //1.如果是叶子节点，直接删除该节点
    //2.如果是非叶子节点，则删除该子树
    public void delNode(int no){
        if(this.left!=null&& this.left.no==no){
            this.left=null;
            return;
        }
        if(this.right!=null&&this.right.no==no){
            this.right=null;
            return;
        }
        if(this.left!=null){
            this.left.delNode(no);
        }
        if(this.right!=null){
            this.right.delNode(no);
        }
    }


    //编写前序遍历方法
    public void preOrder(){
        System.out.println(this);//先输出父节点
        //递归向左子树前序遍历
        if(this.left!=null){
            this.left.preOrder();
        }
        //递归向右子树前序遍历
        if(this.right!=null){
            this.right.preOrder();
        }
    }

    //中序遍历
    public void infixOrder(){
        //递归向左子树中序遍历
        if(this.left!=null){
            this.left.infixOrder();
        }
        //输出父节点
        System.out.println(this);
        //递归向右子树中序遍历
        if(this.right!=null){
            this.right.infixOrder();
        }
    }

    //后序遍历
    public void postOrder(){
        if(this.left!=null){
            this.left.postOrder();
        }
        if(this.right!=null){
            this.right.postOrder();
        }
        System.out.println(this);
    }

    //前序遍历查找
    public HeroNode preOrderSearch(int no){
        System.out.println("执行了前序遍历查找~");
        if(this.no==no){
            return this;
        }
        HeroNode resultNode=null;
        if(this.left!=null){
            resultNode=this.left.preOrderSearch(no);
        }
        if(resultNode!=null){
            return resultNode;
        }
        if(this.right!=null){
            resultNode=this.right.preOrderSearch(no);
        }
        return resultNode;
    }

    //中序遍历查找
    public HeroNode infixOrderSearch(int no){

        HeroNode resNode=null;
        if(this.left!=null){
            resNode= this.left.infixOrderSearch(no);
        }
        if(resNode!=null){
            return resNode;
        }
        System.out.println("执行了中序遍历查找~");
        if(this.no==no){
            return this;
        }
        if(this.right!=null){
            resNode=this.right.infixOrderSearch(no);
        }
        return resNode;
    }
    //后序遍历查找
    public HeroNode postOrderSearch(int no){
        HeroNode resNode=null;
        if(this.left!=null){
            resNode= this.left.infixOrderSearch(no);
        }
        if(resNode!=null){
            return resNode;
        }
        if(this.right!=null){
            resNode=this.right.infixOrderSearch(no);
        }
        if(resNode!=null){
            return resNode;
        }
        System.out.println("执行了后序遍历查找~");
        if(this.no==no){
            return this;
        }else{
            return null;
        }

    }

}
